--- /dev/null
+From 9d449a908099a6dc0779bb1a9e87f5e224909a24 Mon Sep 17 00:00:00 2001
+From: Martin Sperl <kernel@martin.sperl.org>
+Date: Wed, 16 Mar 2016 12:25:01 -0700
+Subject: [PATCH] dmaengine: bcm2835: add slave_sg support to bcm2835-dma
+
+Add slave_sg support to bcm2835-dma using shared allocation
+code for bcm2835_desc and DMA-control blocks already used by
+dma_cyclic.
+
+Note that bcm2835_dma_callback had to get modified to support
+both modes of operation (cyclic and non-cyclic).
+
+Tested using:
+* Hifiberry I2S card (using cyclic DMA)
+* fb_st7735r SPI-framebuffer (using slave_sg DMA via spi-bcm2835)
+playing BigBuckBunny for audio and video.
+
+Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
+Reviewed-by: Eric Anholt <eric@anholt.net>
+Signed-off-by: Eric Anholt <eric@anholt.net>
+Signed-off-by: Vinod Koul <vinod.koul@intel.com>
+---
+ drivers/dma/bcm2835-dma.c | 113 ++++++++++++++++++++++++++++++++++++++++++++--
+ 1 file changed, 108 insertions(+), 5 deletions(-)
+
+--- a/drivers/dma/bcm2835-dma.c
++++ b/drivers/dma/bcm2835-dma.c
+@@ -260,6 +260,23 @@ static void bcm2835_dma_create_cb_set_le
+ control_block->info |= finalextrainfo;
+ }
+
++static inline size_t bcm2835_dma_count_frames_for_sg(
++ struct bcm2835_chan *c,
++ struct scatterlist *sgl,
++ unsigned int sg_len)
++{
++ size_t frames = 0;
++ struct scatterlist *sgent;
++ unsigned int i;
++ size_t plength = bcm2835_dma_max_frame_length(c);
++
++ for_each_sg(sgl, sgent, sg_len, i)
++ frames += bcm2835_dma_frames_for_length(
++ sg_dma_len(sgent), plength);
++
++ return frames;
++}
++
+ /**
+ * bcm2835_dma_create_cb_chain - create a control block and fills data in
+ *
+@@ -361,6 +378,32 @@ error_cb:
+ return NULL;
+ }
+
++static void bcm2835_dma_fill_cb_chain_with_sg(
++ struct dma_chan *chan,
++ enum dma_transfer_direction direction,
++ struct bcm2835_cb_entry *cb,
++ struct scatterlist *sgl,
++ unsigned int sg_len)
++{
++ struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
++ size_t max_len = bcm2835_dma_max_frame_length(c);
++ unsigned int i, len;
++ dma_addr_t addr;
++ struct scatterlist *sgent;
++
++ for_each_sg(sgl, sgent, sg_len, i) {
++ for (addr = sg_dma_address(sgent), len = sg_dma_len(sgent);
++ len > 0;
++ addr += cb->cb->length, len -= cb->cb->length, cb++) {
++ if (direction == DMA_DEV_TO_MEM)
++ cb->cb->dst = addr;
++ else
++ cb->cb->src = addr;
++ cb->cb->length = min(len, max_len);
++ }
++ }
++}
++
+ static int bcm2835_dma_abort(void __iomem *chan_base)
+ {
+ unsigned long cs;
+@@ -428,13 +471,19 @@ static irqreturn_t bcm2835_dma_callback(
+ d = c->desc;
+
+ if (d) {
+- /* TODO Only works for cyclic DMA */
+- vchan_cyclic_callback(&d->vd);
++ if (d->cyclic) {
++ /* call the cyclic callback */
++ vchan_cyclic_callback(&d->vd);
++
++ /* Keep the DMA engine running */
++ writel(BCM2835_DMA_ACTIVE,
++ c->chan_base + BCM2835_DMA_CS);
++ } else {
++ vchan_cookie_complete(&c->desc->vd);
++ bcm2835_dma_start_desc(c);
++ }
+ }
+
+- /* Keep the DMA engine running */
+- writel(BCM2835_DMA_ACTIVE, c->chan_base + BCM2835_DMA_CS);
+-
+ spin_unlock_irqrestore(&c->vc.lock, flags);
+
+ return IRQ_HANDLED;
+@@ -548,6 +597,58 @@ static void bcm2835_dma_issue_pending(st
+ spin_unlock_irqrestore(&c->vc.lock, flags);
+ }
+
++static struct dma_async_tx_descriptor *bcm2835_dma_prep_slave_sg(
++ struct dma_chan *chan,
++ struct scatterlist *sgl, unsigned int sg_len,
++ enum dma_transfer_direction direction,
++ unsigned long flags, void *context)
++{
++ struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
++ struct bcm2835_desc *d;
++ dma_addr_t src = 0, dst = 0;
++ u32 info = BCM2835_DMA_WAIT_RESP;
++ u32 extra = BCM2835_DMA_INT_EN;
++ size_t frames;
++
++ if (!is_slave_direction(direction)) {
++ dev_err(chan->device->dev,
++ "%s: bad direction?\n", __func__);
++ return NULL;
++ }
++
++ if (c->dreq != 0)
++ info |= BCM2835_DMA_PER_MAP(c->dreq);
++
++ if (direction == DMA_DEV_TO_MEM) {
++ if (c->cfg.src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
++ return NULL;
++ src = c->cfg.src_addr;
++ info |= BCM2835_DMA_S_DREQ | BCM2835_DMA_D_INC;
++ } else {
++ if (c->cfg.dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES)
++ return NULL;
++ dst = c->cfg.dst_addr;
++ info |= BCM2835_DMA_D_DREQ | BCM2835_DMA_S_INC;
++ }
++
++ /* count frames in sg list */
++ frames = bcm2835_dma_count_frames_for_sg(c, sgl, sg_len);
++
++ /* allocate the CB chain */
++ d = bcm2835_dma_create_cb_chain(chan, direction, false,
++ info, extra,
++ frames, src, dst, 0, 0,
++ GFP_KERNEL);
++ if (!d)
++ return NULL;
++
++ /* fill in frames with scatterlist pointers */
++ bcm2835_dma_fill_cb_chain_with_sg(chan, direction, d->cb_list,
++ sgl, sg_len);
++
++ return vchan_tx_prep(&c->vc, &d->vd, flags);
++}
++
+ static struct dma_async_tx_descriptor *bcm2835_dma_prep_dma_cyclic(
+ struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
+ size_t period_len, enum dma_transfer_direction direction,
+@@ -778,11 +879,13 @@ static int bcm2835_dma_probe(struct plat
+ dma_cap_set(DMA_SLAVE, od->ddev.cap_mask);
+ dma_cap_set(DMA_PRIVATE, od->ddev.cap_mask);
+ dma_cap_set(DMA_CYCLIC, od->ddev.cap_mask);
++ dma_cap_set(DMA_SLAVE, od->ddev.cap_mask);
+ od->ddev.device_alloc_chan_resources = bcm2835_dma_alloc_chan_resources;
+ od->ddev.device_free_chan_resources = bcm2835_dma_free_chan_resources;
+ od->ddev.device_tx_status = bcm2835_dma_tx_status;
+ od->ddev.device_issue_pending = bcm2835_dma_issue_pending;
+ od->ddev.device_prep_dma_cyclic = bcm2835_dma_prep_dma_cyclic;
++ od->ddev.device_prep_slave_sg = bcm2835_dma_prep_slave_sg;
+ od->ddev.device_config = bcm2835_dma_slave_config;
+ od->ddev.device_terminate_all = bcm2835_dma_terminate_all;
+ od->ddev.src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
projects / openwrt / staging / yousong.git / blobdiff